Complications and side effects of high-dose-rate prostate brachytherapy

The prognostic significance of the clinical T stage and Grade Group in patients with locally advanced prostate cancer treated via high-dose-rate brachytherapy and external beam radiation

BACKGROUND

Although the optimal management of locally advanced prostate cancer (PCa) remains unclear, local definitive therapy, thus combined radiotherapy and androgen deprivation, is one option. We evaluated the long-term outcomes of patients with locally advanced PCa who underwent high-dose-rate brachytherapy (HDR-BT) and external beam radiation therapy (EBRT).

METHODS

We retrospectively analyzed 173 patients with locally advanced PCa (cT3a-4N0-1M0) who underwent HDR-BT and EBRT. We employed Cox's proportional hazards models to identify pre-treatment predictors of oncological outcomes. Treatment outcomes (biochemical recurrence-free survival [BCRFS], clinical progression-free survival [CPFS], and castration-resistant prostate cancer-free survival [CRPCFS] were compared according to the combination of the pre-treatment predictors.

RESULTS

The 5-year BCRFS, CPFS, and CRPCFS rates were 78.5, 91.7, and 94.4% respectively; there were two PCa deaths. Multivariate analysis revealed that the clinical T stage (cT3b and cT4) and Grade Group (GG) 5 status were independent risk factors for poor BCRFS, CPFS, and CRPCFS. In the GG ≤ 4 group, the Kaplan-Meier curves for BCRFS, CPFS, and CRPCFS revealed excellent outcomes. However, in the GG5 group, patients with cT3b and cT4 PCa evidenced significantly poorer oncological outcomes than those with cT3a PCa.

CONCLUSION

The clinical T stage and GG status were significantly prognostic of oncological outcomes in patients with locally advanced PCa. In patients of GG ≤ 4 PCa, HDR-BT was effective even in patients with cT3b or cT4 PCa. However, in patients with GG5 PCa, careful monitoring is essential, particularly of patients with cT3b or cT4 PCa.

Does brachytherapy boost improve survival outcomes in Gleason Grade Group 5 patients treated with external beam radiotherapy and androgen deprivation therapy? A systematic review and meta-analysis

•

Adding a BT boost to external beam radiation can be used to intensify treatment.

•

BT boost improves DMFS but not PCSS or OS in Gleason GG5 prostate cancer.

•

There is no prospective data evaluating BT boost in Gleason GG5 disease.

Background

Localized Gleason Grade Group 5 (GG5) prostate cancer has a poor prognosis and is associated with a higher risk of treatment failure, metastases, and death. Treatment intensification with the addition of a brachytherapy (BT) boost to external beam radiation (EBRT) maximizes local control, which may translate into improved survival outcomes.

Methods

A systematic review and meta-analysis was performed to compare survival outcomes for Gleason GG5 patients treated with androgen deprivation therapy (ADT) and either EBRT or EBRT + BT. The MEDLINE (PubMed), EMBASE and Cochrane databases were searched to identify relevant studies. Survival probabilities for distant metastasis-free survival (DMFS), prostate cancer-specific survival (PCSS), and overall survival (OS) were extracted and pooled to create a summary survival curve for each treatment modality, which were then compared at fixed points in time. An additional analysis was performed among studies directly comparing EBRT and EBRT + BT using a random-effects model.

Results

Eight retrospective studies were selected for inclusion, representing a total of 1393 EBRT patients and 877 EBRT + BT patients. EBRT + BT was associated with higher DMFS starting at 6 years (86.8 % vs 78.8 %; p = 0.018) and extending out to 10 years (81.8 % vs 66.1 %; p < 0.001), with an overall hazard ratio of 0.53 (p = 0.02). There was no difference in PCSS or OS between treatment modalities. Differences in toxicity were not assessed. There was a wide range of heterogeneity between studies.

Conclusion

The addition of BT boost is associated with improved long-term DMFS in Gleason GG5 prostate cancer, but its impact on PCSS and OS remains unclear. These results may be confounded by the heterogeneity across study populations with concern for a risk of bias. Therefore, prospective studies are necessary to further elucidate the survival advantage associated with BT boost, which must ultimately be weighed against the toxicity-related implications of this treatment strategy.

High-Dose-Rate Brachytherapy as Monotherapy for Low- and Intermediate-Risk Prostate Cancer. Oncological Outcomes After a Median 15-Year Follow-Up

Introduction

To evaluate the oncological outcome of high dose rate (HDR) brachytherapy (BRT) as monotherapy for clinically localised prostate cancer (PCA).

Material and Methods

Between January 2002 and February 2004, 141 consecutive patients with clinically localised PCA were treated with HDR-BRT monotherapy. The cohort comprised 103 (73%) low-, 32 (22.7%) intermediate- and 6 (4.3%) high risk patients according to D’Amico classification or 104 (73.8%) low-, 24 (17.0%) intermediate favourable-, 12 (8.5%) intermediate unfavourable- and one (0.7%) very high risk patient according to National Comprehensive Cancer Network (NCCN) one. Patients received four fractions of 9.5 Gy delivered within a single implant up to a total physical dose of 38 Gy. Catheter-implantation was transrectal ultrasound-based whereas treatment planning CT-based. Thirty-three patients (23.4%) received ADT neoadjuvantly and continued concurrently with BRT. Biochemical relapse-free survival (BRFS) was defined according to the Phoenix Consensus Criteria and genitourinary (GU)/gastrointestinal (GI) toxicity evaluated using the Common Toxicity Criteria for Adverse Events version 5.0.

Results

Median age at treatment and median follow-up time was 67.2 and 15.2 years, respectively. Twenty-three (16.3%) patients experienced a biochemical relapse and 5 (3.5%) developed distant metastases, with only one patient dying of PCA. The BRFS was 85.1% at 15 years and 78.7% at 18 years. The corresponding overall survival, metastases-free survival, and prostate cancer specific mortality at 15- and 18-years was 73.9%/59.1%, 98.3%/90.6%, and 100%/98.5% respectively. Late grade 3 GI and GU toxicity was 4.2% and 5.6% respectively. Erectile dysfunction grade 3 was reported by 27 (19%) patients. From the prognostic factors evaluated, tumor stage (≤T2b compared to ≥T2c) along with the risk group (low-intermediate vs. high) when using the D’Amico classification but not when the NCCN one was taken into account, correlated significantly with BRFS.

Conclusion

Our long-term results confirm HDR-BRT to be a safe and effective monotherapeutic treatment modality for low- and intermediate risk PCA.